Table 2.
Comparison between the daily solar radiant exposure in São Paulo (SP), Brazil, and the radiant exposure provided by the lamp over a 50-h period (distance between sunglasses and lamp is 300 mm) for 2 specific days of the year: the shortest (day 172) and longest (day 355) days
| Radiant exposure (MJ m−2) | Photoperiod (h) | Lamp–sun equivalence (days) | ||||
|---|---|---|---|---|---|---|
| Solar | Lamp | |||||
| Direct | Diffuse | Global | Direct | |||
| From peak to peak | ||||||
| Day 172 | 1.5 | 0.5 | 2.0 | 7.8 | 4.0 | 4 |
| Day 355 | 2.3 | 1.4 | 3.7 | 7.8 | 8.6 | 2 |
| Daily average | 2.1 | 1.0 | 3.2 | 7.8 | 6.9 | 2 |
| Lamp | 50.0 | |||||
| From sunrise to sunset | ||||||
| Day 172 | 3.0 | 1.0 | 4.0 | 7.8 | 10.7 | 2 |
| Day 355 | 3.3 | 1.7 | 5.0 | 7.8 | 13.6 | 2 |
| Daily average | 3.2 | 1.4 | 4.6 | 7.8 | 12.1 | 2 |
| Lamp | 50.0 | |||||
| First band peak only | ||||||
| Day 172 | 0.4 | 0.1 | 0.5 | 7.8 | 1.0 | 16 |
| Day 355 | 0.4 | 0.1 | 0.5 | 7.8 | 1.0 | 16 |
| Daily average | 0.4 | 0.1 | 0.5 | 7.8 | 1.0 | 16 |
| Lamp | 50.0 | |||||
In addition, the daily average is shown